Increased frequency and severity of developmental deformities in rough-skinned newt (Taricha granulosa) embryos exposed to road deicing salts (NaCl & MgCl2)

Road-side aquatic ecosystems in North America are annually polluted with millions of tons of road deicing salts, which threaten the survival of amphibians which live and breed in these habitats. While much is known of the effects of NaCl, little is known of the second most-commonly used deicer, MgCl2, which is now used exclusively in parts of the continent. Here we report that environmentally relevant concentrations of both NaCl and MgCl2 cause increased incidence of developmental deformities in rough-skinned newt hatchlings that developed embryonically in these salts. In addition, we provide some of the first quantification of severity of different deformities, and reveal that increased salt concentrations increase both deformity frequency and severity. Our work contributes to the growing body of literature that suggests salamanders and newts are particularly vulnerable to salt, and that the emerging pollutant, MgCl2 is comparable in its effects to the more traditionally-used NaCl.

► Rough-skinned newt embryos were raised in NaCl and MgCl2 road deicing salts.
► We quantified the frequency and severity of resulting developmental deformities.
► Both salts caused increased frequency and severity of developmental deformities.
► Effects of MgCl2, an emerging stressor, are comparable to traditionally-used NaCl.
► Newts and salamanders may be more susceptible to road salt than frogs and toads.